Currently, Computer Aided Design (CAD) dentistry utilizes either a set of impression trays to make a mold of a patient's teeth or dental arch, which is filled with plaster to create a model of the patient's teeth. The plaster model of the patient's teeth is then scanned using a 3D laser scanner, or optionally an intraoral 3D scanning system can be utilized to create a digital 3D model of the patient's teeth or dental arch. The digital models of the upper and lower dental arch within the CAD program are then “mounted” in a digital representation of a dental articulator to allow the dentist or dental technician to design a crown or bridge or orthodontic procedure. These articulators are simply digital copies of the physical articulators currently on the market. The dentists or the dental technician then creates the CAD dental restoration, crown or bridge, or an orthodontic procedure to align the patient's teeth. For dental restorations, the CAD program will utilize a library of teeth, in some cases up to 300 different tooth models to design a crown or multiple teeth to design a bridge or full upper or lower dental arch. Once completed, the restoration is sent to a milling lab to be manufactured. Once milled, the restoration is returned to the dentist for “try-in” and fitting. This fitting requires the dentist to match the restoration to the patient's jaw movements and dental function or occlusion. For an orthodontic procedure, the digital dental model is separated into the patient's individual teeth, and the teeth are then moved in incremental steps until the ultimate alignment is achieved. FIG. 1 is representative of a typical Dental CAD system comprised of a 3-D Laser Scanner 10 and a computer workstation which includes a computer 12, monitor 14 and keyboard 16. FIG. 3 shows digital model of a typical dental articular which is used to hold models of an upper dental arch 127 and a lower dental arch 137 and allow the user to simulate the movement of the jaw when fabricating dental restorations such as crowns, bridges, and dentures. Use of a virtual articulator in conjunction with the invention is described in greater detail below.
The purpose of a dental articulator is to simulate the jaw or condylar movements of a patient. This instrument enables a dentist to verify the contact points between opposing teeth for dental restorations such as a crown or bridge or, for orthodontics, the contact points of the tooth surfaces themselves. FIG. 2 is representative of standard articulator used within the dental industry, which includes upper and lower frame sections 20, 22, which hold an articulating model formed from casts or impressions of the upper and lower teeth of a patient (not shown), respectively. The upper frame section is mounted to rotate about an axis 24, linearly relative to the lower frame section. An adjustable rod 26 can be used to maintain spacing the operator deems to be appropriate between the upper and lower teeth.
U.S. Pat. No. 7,412,298 issued to the inventors herein, entitled “Method and System for Morphometric Analysis of Human Dental Occlusal Function and Uses Thereof” (hereinafter referred to as “the '298 Patent”), demonstrates a mathematical method for analyzing jaw motion by calculating the shape of Temporomandibular Joint (TMJ) from the wear surfaces of at least two teeth of the patient's upper or lower jaw. The same mathematical method can be used to solve for the individual's dynamic occlusal function if the shape of the TMJ has previously been solved using the U.S. Pat. No. 7,412,298, or has been measured using a scanning method such as a CAT Scan. Pending U.S Patent application US2011/032674 demonstrates a method for creating dental restorations in a similar analog method, this method can be used to make a single crown, partials, bridges or full dental arches, or develop a orthodontic treatment. This patent describes a method to manufacture dental restorations for an edentulous patient using “Eric's Rims” to record the patient's dynamic occlusion. All of the mathematical formulations and details of the methods disclosed in U.S. Pat. No. 7,412,298, and the details for using Eric's Rims in pending application US2011/032674, are incorporated herein as though fully set forth.
While there are multiple commercially available CAD systems for the manufacture of Dental Restorations and for the development of orthodontic treatment plans, and while these methods have been available for some time, the methods employed do not attempt to record or calculate each patent's particular TMJ or dynamic occlusal function. The systems currently in place utilize digital models of linear articulators, of the type shown in FIG. 2, which create a linear duplication of the condylar guidance, or rely on the static contact of the upper and lower teeth to design the contact of wear surfaces.
Thus, there is a need for an advanced method to replicate accurately the unique path of motion of a patient's dynamic occlusion when creating a dental restoration in a CAD system.